The Roman Colosseum Presents: Ludi of Janus, Roman god of Beginnings and Endings

In ancient Roman religion and myth, Janus (/ˈdʒeɪnəs/ JAY-nəs; Latin: Ianvs [ˈi̯aːnʊs]) is the god of beginnings, gates, transitions, time, duality, doorways,^[2] passages, frames, and endings. He is usually depicted as having two faces. The month of January is named for Janus (Ianuarius).^[3] According to ancient Roman farmers' almanacs, Juno was mistaken as the tutelary deity of the month of January,^[4] but Juno is the tutelary deity of the month of June.

Janus presided over the beginning and ending of conflict, and hence war and peace. The gates of a building in Rome named after him (not a temple, as it is often called, but an open enclosure with gates at each end) were opened in time of war, and closed to mark the arrival of peace. As a god of transitions, he had functions pertaining to birth and to journeys and exchange, and in his association with Portunus, a similar harbor and gateway god, he was concerned with travelling, trading and shipping.

Numa built the Ianus geminus (also Janus Bifrons, Janus Quirinus or Portae Belli), a passage ritually opened at times of war, and shut again when Roman arms rested.^[54] It formed a walled enclosure with gates at each end, situated between the old Roman Forum and that of Julius Caesar, which had been consecrated by Numa Pompilius himself. About the exact location and aspect of the temple there has been much debate among scholars.^[55] In wartime the gates of the Janus were opened, and in its interior sacrifices and vaticinia were held, to forecast the outcome of military deeds.^[56] The doors were closed only during peacetime, an extremely rare event.^[57] The function of the Ianus Geminus was supposed to be a sort of good omen: in time of peace it was said to close the wars within or to keep peace inside;^[which?] in times of war it was said to be open to allow the return of the people on duty.^[58]

A temple of Janus is said to have been consecrated by the consul Gaius Duilius in 260 BC after the Battle of Mylae in the Forum Holitorium. It contained a statue of the god with the right hand showing the number 300 and the left the number 65—i.e., the length in days of the solar year, and twelve altars, one for each month.^[59]

^{Janus - Wikipedia}